1. Field of the Invention
This invention relates to a secondary contact assembly which couples a circuit breaker and a circuit breaker enclosure, and, more specifically, to an adjustable circuit breaker portion of a secondary contact assembly that may be adjusted to couple a circuit breaker which is being retrofitted in a variety of circuit breaker enclosures.
2. Background Information
Power circuit breakers typically are mounted in a cabinet or enclosure. The enclosure includes a plurality of main contact busses or stabs which are coupled to the main quick disconnects of the circuit breaker. The enclosure further includes a secondary contact assembly which is coupled to the control mechanism of the circuit breaker, as well as other components described below. The control mechanism will trip the circuit breaker and separate the main contacts when an over current condition is sensed.
The secondary contact assembly includes two portions; a portion located on the circuit breaker enclosure and a corresponding portion on the circuit breaker. The secondary contact assembly may be located between the circuit breaker and a variety of components such as current transformers, voltage transformers, relays, switches in other circuit breakers, or sensor equipment. Circuit breakers typically have the circuit breaker portion of the secondary contact assembly on the outside of the circuit breaker. The circuit breaker portion of the secondary contact assembly is coupled to the control mechanism. The circuit breaker portion of the secondary contact assembly includes a plurality of spring biased, elongated members, or tabs. The enclosure portion of the secondary contact assembly also includes a plurality of finger like contact terminals. The finger like contact terminals are attached to a base member. Each contact terminal extends from the base and is flexible. Each contact terminal may be coupled to a variety of components such as current transformers, voltage transformers, relays, switches in other circuit breakers, or sensor equipment.
When the circuit breaker is inserted into the enclosure, each tab of the secondary contact assembly comes into contact with a contact terminal. Electricity passes from the circuit breaker to components such as current transformers, voltage transformers, relays, switches in other circuit breakers, or sensor equipment.
Different enclosures for different model circuit breakers have different shaped secondary contact assemblies. For example, the Federal Pacific xe2x80x9cFPxe2x80x9d vintage circuit breaker has a secondary contact assembly having four poles spaced on 1.25 inch center lines, while the xe2x80x9cFPSxe2x80x9d and General Electric AK series circuit breaker has a secondary contact assembly having seven poles spaced on 0.75 inch center lines. The Westinghouse DB series circuit breakers also have secondary contact assemblies with 1.25 centerlines. The ITE KA series circuit breaker has 0.875 inch centerlines for its secondary contact assemblies.
It is desirable to replace older circuit breakers with newer circuit breakers without having to replace the circuit breaker enclosure. One alternative would be to manufacture various models of the replacement circuit breaker, each having a secondary contact assembly which emulates a prior circuit breaker. This would, however, result in increased manufacturing costs and limit the usefulness of the replacement circuit breaker. It would be more efficient and convenient to have a single replacement breaker with an adjustable circuit breaker portion of the secondary contact assembly which could be assembled to match the enclosure portion of the secondary contact assembly.
There is, therefore, a need for an adjustable circuit breaker portion of a secondary contact assembly for a circuit breaker that may be adapted to be used with various circuit breaker enclosures.
There is a further need for an adjustable circuit breaker portion of a secondary contact assembly that may be assembled to match an enclosure at the insulation site.
There is a further need for an adjustable circuit breaker portion of a secondary contact assembly which may be assembled to match various enclosure using common components.
These needs and others are met by the invention which provides a secondary contact assembly made from individual contact units, spacers and a mounting rail.
The contact assembly is assembled by placing individual contact units on the mounting rail. The contact units may be maintained in a proper spaced relation by the spacers. When the contact units and spacers, if required, are assembled on the mounting rail in the proper order, each component is attached to the mounting rail. The contact units may be attached by any common method such as ultrasonic welding, glue, or a friction fit.
The contact units may be manufacturing to have a width of 0.625 inches. The spacers may have a thickness of 0.125 inches. Contact units and spacers having these dimensions can be assembled into secondary contact assemblies which may engage most prior art circuit breakers enclosures.